Some minor polish from tourist branch (#949)

- Replace per-type fmt::formatter specializations (StringBuilderBase, NiceBase) with a single generic formatter using a HasStringViewConversion concept
- Add ThousandsNum for comma-separated integer formatting (e.g. "1,234,567")
- Thread naming now accepts a sort hint for trace ordering
- Fix main thread trace registration to use actual thread ID and sort first
- Add ExpandEnvironmentVariables() for expanding %VAR% references in strings, with tests
- Add ParseHexBytes() overload with expected byte count validation
- Add Flag_BelowNormalPriority to CreateProcOptions (BELOW_NORMAL_PRIORITY_CLASS on Windows, setpriority on POSIX)
- Add PrettyScroll progress bar mode that pins the status line to the bottom of the terminal using scroll regions, with signal handler cleanup for Ctrl+C/SIGTERM

1 files changed, 28 insertions, 0 deletions

diff --git a/src/zencore/string.cpp b/src/zencore/string.cpp
index 358722b0b..df7d71250 100644
--- a/src/zencore/string.cpp
+++ b/src/zencore/string.cpp
@@ -381,6 +381,34 @@ NiceNumGeneral(uint64_t Num, std::span<char> Buffer, NicenumFormat Format)
 }
 
 size_t
+ThousandsToBuffer(uint64_t Num, std::span<char> Buffer)
+{
+	// Format into a temporary buffer without separators
+	char Tmp[24];
+	int	 Len = snprintf(Tmp, sizeof(Tmp), "%llu", (unsigned long long)Num);
+
+	// Insert comma separators
+	int SepCount = (Len - 1) / 3;
+	int TotalLen = Len + SepCount;
+	ZEN_ASSERT(TotalLen < (int)Buffer.size());
+
+	int Src		  = Len - 1;
+	int Dst		  = TotalLen;
+	Buffer[Dst--] = '\0';
+
+	for (int i = 0; Src >= 0; i++)
+	{
+		if (i > 0 && i % 3 == 0)
+		{
+			Buffer[Dst--] = ',';
+		}
+		Buffer[Dst--] = Tmp[Src--];
+	}
+
+	return TotalLen;
+}
+
+size_t
 NiceNumToBuffer(uint64_t Num, std::span<char> Buffer)
 {
 	return NiceNumGeneral(Num, Buffer, kNicenum1024);